This invention relates generally to printers. More specifically, it relates to an attachment for a computer controlled impact printer that allows a conventional one-color printer to print in any of two or more colors.
Many conventional printers, particularly printers designed for use as computer output devices, are impact printers where a printhead impacts a character against an inked ribbon and an underlying sheet of paper. Typically the printhead translates back and forth across the paper under the control of a host computer or data source.
One limitation on conventional printers is that they normally are capable of printing in only one color, typically black. The ribbon, if a ribbon is used, carries ink of only one color. While printers are available which can print in more than one color--with changes between colors occurring during a continuous printing operation--these devices are more complicated. They require a different printhead, control logic and other modifications. They are also significantly more expensive than comparable one-color printers. Heretofore there has been no mechanism or system which would give a standard one-color printer the capability of printing in two or more colors. In particular there has been no such device or system which could be readily attached to existing printers.
It is therefore a principal object of this invention to provide a mechanism that allows a conventional one color printer to print in multiple colors.
Another principal object is to provide such a multicolor capability with no alterations or only minor alterations in the construction of the conventional printer.
A further object is to provide conversion between colors during a printing operation under the control of a computer or data source.
Another object of this invention is to provide a mechanism with the foregoing advantages which has a comparatively low cost of manufacture.
A further object is to provide such a mechanism which is replaceable and which does not interfere with the normal printing operation.
Yet another object is to provide a multicolor capability which allows an "initialization" to ensure that the printing operation begins with a predetermined color.
A further object is to provide a mechanism with the foregoing advantages that is compact and reliable.